Blocked Intakes Cause Performance Loss in Diesel Engines

Modern diesels are sophisticated pieces of automotive engineering, not the sometimes crude, heavy and slow things of the past. They require equally sophisticated maintenance and this brings a range of new problems and solutions

The Problem

One of these new problems we see at Howell Automotive is clogged intake ports and manifolds of modern diesel engines in cars and 4WDs, caused by deposits from the Exhaust Gas Recirculation (EGR) system and the Positive Crankcase Ventilation (PCV) system.

Deposits on the intake area of a diesel engine

These systems take gasses from the exhaust and crankcase and introduce them back into the intake area to be burnt. Both sources contain by products of the combustion process including carbon from the exhaust system.

While the carbon build up from the EGR system by itself can be a long term problem, when you add wet crankcase gasses from the PCV system (engine fumes) the problem becomes more serious. The combination of the wet crankcase gasses and the dry exhaust gas creates a sludge that sticks to the intake ports in the engine manifold and blocks them, choking the engine and resulting in a loss of power and efficiency and the engine may eventually start to miss.

What are EGRs and PCVs and Why Do We Need Them

The EGR system's original purpose was to reduce emissions, as engineers found that lowering the exhaust gas temperatures by introducing recycled exhaust gasses into the fresh air fuel mixture helps reduce the amount of sulphur dioxide, and nitrogen oxides released into the atmosphere. This influences the engines optimum operating temperature. Excessive heat is the enemy of engines and particularly turbo chargers, so a properly functioning EGR system is essential for long term engine life.

Diesel engines operate at higher internal pressures then petrol engines resulting in significant amount of gas being forced past the piston rings down into the engine crankcase and this will eventually pressurize, and blow out seals and gaskets.

Another significant component of crankcase gasses is the wet oil mist created by the crankshaft rotating rapidly in the sump's oil bath. The old solution for cars and trucks was to vent the crankcase gases straight out into the atmosphere. As part of the push to reduce vehicle engine emissions the practice of atmospheric venting is no longer acceptable. In modern engines the combined emissions are recycled and managed in the combustion process.

Diesel engines operating in enclosed spaces also faced the problem of venting the crankcase and this where the PCV technique of piping these gases into the intake system comes from.

The Howell Automotive Solution

Howell Automotive's system feeds the crankcase vent gas into a filter and oil separation unit before recycling into the diesel engine's intake system.

The system separates out the sticky "wet" oil mist and returns the oil to the crankcase leaving a dry gas going into the intake system. Not only does this reduce deposits in the engine intake area but provides the additional benefit of reducing oil consumption, as oil is not lost in the venting process.

The filtration system removes the large solids coming from the crankcase vent and this system is easily maintained with filter inserts replaced as part of Howell Automotive's normal servicing program.

In conjunction with retrofitting this type of fix, Howell Automotive cleans the intake system to restore normal performance and economy while their venting system helps keep the engine cleaner longer.